At present, various methods of treatment of eye pathologies—surgical and medicamental, are applied in medical practice. Medicamental methods usually comprise natural and synthetic compounds possessing antioxidant properties (antioxidants).
In pathogenesis of many eye pathologies (including cataract and macular dystrophy), the oxidative stress—disruption of the balance between production of free radicals and their elimination by antioxidants, plays an important role.
Only bioactive nutrients containing natural carotenoids possessing antioxidant properties—lutein and zeaxanthin have been available in Russia to date. Said compounds also contain plant carotenoid beta-carotene (1.5 mg) that plays an important role in the formation of a visual pigment rhodopsin providing an eye with adaptation to the lowered lighting; antioxidants—vitamins E and C, micronutrients zinc and copper which are also important to maintain the health of eyes.
Age-related macular degeneration (AMD) occupies a highly important place in the world among disorders leading to persistent deterioration of visual functions and blindness (J. Evans, C. Rooney, F. Ashood, 1996). AMD is one of the eye diseases which are difficult to treat (L. N. Marchenko, 2001). The Russian Central Scientific Research Institute of Expertise of Work Capability and Organization of Labor of the Disabled reported in 1997 that the vascular diseases of retina resulting in eye disability in particular comprise nonexudative age-related macular degeneration—39.4%, exudative age-related macular degeneration—9.1%, bloodstream disruption in great retina vessels—51.5%. Age-related macular degeneration constituted about 10% of blindness registered in the Western Europe 25 years ago, this value has increased up to 50% to date (V. S. Akopyan, 2004). According to the reports of WHO/OMS (1986), increase in proportion of elders within the human population leads to annual increase in said disease. The history of macular degeneration problem originated from 1855 when F. S. Donders described macular drusen. The term “senile macular degeneration” was first introduced by O. Haab in 1885. Later on, C. Behr (1920) and H. F. Falls (1949) assigned said pathology to hereditary familial diseases. Taking into account a variety of clinical and opthalmoscopic data, different terms have been applied to age-related macular degeneration in the literature. To date a consensus exists among ophthalmologists that all these pathology types are a manifestation of the same disease that now is often designated in the literature as “age-related macular degeneration” (AMD).
AMD is a pathology of central photoactive area of retina. The disease is a chronic dystrophic process when choriocapillaries, Bruch's membrane and pigment retinal epithelium are predominantly affected followed by the affection of photoreceptors (V. S. Lysenko et al., 2001). The extent of the process severity and the loss of central vision depends on AMD type and vicinity of dystrophic process to central fossa of retina. AMD is most commonly double-sided process. The second eye was observed to be affected within 5 years after the affection of the first eye (H. C. Zweng, 1977).
Progression of macular degeneration results in increased light sensitivity, eyesight degradation, gradual loss of eyeshots, and finally appearance of turbid spot in the center of visual field (relative or absolute scotoma). The reasons resulting in macular degeneration are different. However the role of genetic factors and damaging action of light are undoubted. At present, the consequences of negative effect of free oxygen radicals are often discussed in the scientific literature. Photochemical reaction induced by light and oxygen results in the formation of highly reactive free radicals which are capable for damaging light sensitive cells of eye retina. The older is a person, the more dangerous is the effect of free radicals—natural aging correlates with decline of the activity of intrinsic protective antioxidant system of an organism that accelerates dystrophic processes.
Prolonged computer work also leads to eyesight degradation. Computer monitor is a source of serious hazard to eyes since it radiates ultraviolet light, the effect of the latter is enhanced when luminescent lamps are used. Coupled with hard work of eyes, this can cause fast exhaustion, headaches, decrease in capability for work, eye pain, lachrymation. According to statistics, from 50% to 90% of persons engaged in computer working have such complaints when see a doctor. These complaints are combined into the term “computer vision syndrome”. To increase antioxidant protection of eyes, persons engaged in computer working need additional administration of antioxidants.
Vitamins-antioxidants such as vitamins C and E, bioflavonoids, beta-carotene also protect eyes from damaging and facilitate anabolic processes supporting collagen biosynthesis. Combined administration of N-acetyl-cysteine, lipoic acid and vitamins C and E stimulates biosynthesis of antioxidant enzymes of eye tissue, glutathione.